A British crew member who became ill after a suspected outbreak of hantavirus on a luxury cruise ship in the Atlantic Ocean is to be medically evacuated, officials have said.

The crew member is being prepared for medical evacuation from the MV Hondius along with a Dutch colleague, with Dutch authorities overseeing the operation. The two crew members needed “urgent medical care” after experiencing respiratory symptoms, the tour operator Oceanwide Expeditions said.

Dr Maria Van Kerkhove, from the World Health Organization (WHO), said its “highest priority” was to “medically evacuate these two individuals to make sure that they have the care that they [need]”.

A British passenger with symptoms of hantavirus, a disease primarily found in rodents, is understood to be improving. The passenger was medically evacuated on 27 April to Johannesburg, and remains in intensive care.

The UK prime minister said the government was putting “plans in place” for the onward travel of Britons stuck on the Dutch-flagged cruise ship.

In a post on X, Keir Starmer said: “My thoughts are with those affected by the hantavirus outbreak onboard the MV Hondius. We are working closely with international partners to support British nationals onboard and we’re putting plans in place for their safe onward travel.”

A total of seven suspected cases have been identified, including three people who have died. Two of the cases have been confirmed as hantavirus.

Van Kerkhove said: “As of today, seven individuals of the 147 passengers and crew have been reported ill. Sadly, three have died.

“One patient is in intensive care in South Africa, although we understand that this patient is improving, while two patients are still onboard the ship and are being prepared for medical evacuation to the Netherlands for treatment.”

Another suspected case has been reported, but this person was “currently doing well and is asymptomatic”, Van Kerkhove added.

“At this stage, there are no additional symptomatic people onboard. That said, the situation is being closely monitored and, as a precaution, passengers have been asked to remain in their cabins while disinfection and other public health measures are carried out,” she added.

There are 19 British nationals listed as passengers and four British crew members on the ship, which was sailing from Argentina to Cape Verde.

A UK government spokesperson said: “We are working with the Dutch government on medical evacuation planning for sick passengers with the local authorities from a range of nationalities, but that includes one British national as well.”

Medical teams from Cape Verde are providing support to the ship. Van Kerkhove said it would move to the Canary Islands, where investigations and a full disinfection of the ship would take place. The WHO said that it “assesses the risk to the global population as low”.

A Dutch passenger died onboard the ship on 11 April. His wife died on 27 April, with authorities later confirming she had tested positive for a variant of hantavirus. On 2 May, a German passenger died, although the cause has not yet been confirmed.

Oceanwide Expeditions said in a statement that the atmosphere on the ship “remains calm, with passengers generally composed”. The company added that it was “working to provide clarity and reassurance to guests and expedite their disembarkation and medical screening”.

Hantavirus infections, which are usually spread by infected rodents’ urine or faeces, can lead to severe respiratory illness and can sometimes be fatal. While rare, infections can spread between people, according to the WHO.

There is no specific treatment or cure, but patients have a better chance of survival if they receive medical attention early.